In Game B, use the top right portal and pick up one of the grey statues with Space bar. Put it in the microwave. Do the same thing with the other statue. The codes you'll receive for them are (9459) and (9990).
Input both of those codes in the Game A. Put all of your statues in the right room. You get two of them from the microwave codes, and the third one from the main A room.
Put all of the statues around the portal in the right room in Game A. All of the statues should be looking at the portal in order to activate it.
The red-eyed statue goes to the left to the portal, the yellow-eyed statue goes one tile below the portal, and the pink-eyed statue should be put in the top-right corner of the room. Activate the portal and get into the final room.

PICS OF THE STATUES
https://imgur.com/a/gKm37oE


In Game B, check out the light switches on the wall, then in Game A, set up the lights in the same pattern.
After setting up the lights in the right pattern, go through the portal and pick up the fire extinguisher.
Put the fire extinguisher in your microwave. You'll get the code (4719).
Input the code (4719) in the Game B. You'll receive the fire extinguisher.
Go back to the Game B, extinguish the fire with the extinguisher, use the portal, go to the final microwave and press Y. Do the same in Game A.